Many industrial processes, especially the petrochemical industry, require the accurate, dependable measurement of temperature outside the surface or skin of tubes, pipes or conduits within a furnace or other vessel. The information gained thereby may allow the avoidance of overheating and possible rupture. To detect potential overheating situations, measuring devices, such as thermocouples, may be placed at locations expected to encounter the highest radiation and flame exposure. A common problem encountered involves the generally short life of unprotected thermocouples which are exposed to these temperature extremes. Further, since it is generally necessary to attach the measuring devices, i.e., the thermocouple cables, to the pipe whose temperature is being measured, usually by welding, thermocouple replacement is both time consuming and expensive. Normally, such replacement may occur only during process shut down. To replace such a thermocouple, the old assembly must normally be ground from the outside surface of the pipe, the operator taking extreme care not to weaken the pipe by grinding beneath the surface of the pipe. A replacement thermocouple would then be welded to the pipe and connected to the monitoring system. It is to the dual problems of thermocouple removal and reinstallation that Applicant's invention is directed.